• Journal of the Korean Geotechnical Society
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• v.34 no.5
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• pp.19-35
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• 2018

The necessity of predicting the spatial information of the site-specific seismic response, which is essential information for the comprehensive earthquake disaster countermeasures, is increasing for the mid-west urban areas where the earthquake-induced damages can be increased due to frequent occurrence of mid-scale earthquake such as 2016 Gyeongju Earthquake and 2017 Pohang Earthquake. Especially, researches on strategic securing of site survey datasets and understanding the site-specific site response characteristics were conducted for Gyeonggi-do, South Korea. In this study, a GIS-based framework for site-specific assessment of site response and induced vulnerable area in Gyeonggi-do, South Korea was proposed. Geo-Data based on GIS platform was constructed for regional estimation of geotechnical characteristics by collecting borehole and land coverage datasets. And the geo-spatial grid information was developed for deriving spatial distribution of geotechnical layer and site response parameters based on the optimization of the geostatistical interpolation method. Accordingly, base information for Improving earthquake preparedness measures was derived as seismic zonation map with administrative sub-units considering the quantitative site effect of Gyeonggi-do.

• Journal of the Korean earth science society
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• v.40 no.1
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• pp.56-67
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• 2019

In this study, we analyzed the intensity attenuation for M 6.0, 6.5, and 7.0 earthquakes using the broadband strong ground motion simulation platform based on the physical seismic modeling developed by the US Southern California Earthquake Center (SCEC). The location of the earthquake was assumed to be near the epicenter of the 2016 M 5.8 Gyeongju earthquake, but two of the representative US regional models provided by the SCEC strong ground motion simulation platform were used for the propagation model. One is the Central and Eastern United States (CEUS) model representing the intraplate region, and the other is the LA Basin model representing the interplate region. Five modeling methodologies are presented in the version 16.5 of the simulation platform, and Song and Exsim models were used in this study. In the analysis, we found that different intensity attenuation patterns can be observed with the same magnitude of earthquakes, especially depending on the region (CEUS vs LA Basin). Given the same magnitude and distance, the instrumental intensity in the CEUS region (intraplate) could be larger by a unit of 2 than that in the LA Basin region (interplate). Given the difference of intensity attenuation patterns observed in the study, it is important to know the regional intensity attenuation characteristics to understand the accurate level of seismic hazard imposed in the Korean Peninsula. This study also shows the level of the uncertainty of intensity attenuation if region specific attenuation characteristics are not considered.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.272-282
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• 2019

Although the knowledge of current seismicity is a critical information for making and implementing effective earthquake-related policy, the detailed seismicity information of the metropolitan areas with high-population density has been largely underestimated due to the high-level of cultural noise and small earthquake magnitude. This study presents 12 earthquakes including 2 earthquakes previously known and 10 additional earthquakes occurred from 2010 to 2017 in Busan, but they were unreported by the Korea Meteorological Administration. Matched filter technique is used to detect micro-earthquakes. Although the epicenters of micro-earthquakes though present a distinguished linearity, a correlation with faults in the area is unknown. A repeated micro-seismicity suggests that there are subsurface structures responsible for observed events. If large earthquakes occur along the fault in Busan, they may cause catastrophic natural disasters. Given the fact that the recent earthquakes did not accompany any surface signatures, it is highly recommended that the current micro-seismicity be investigated, and updated seismicity information be incorporated into establishing active fault maps in Korea.

• Journal of the Korean Geophysical Society
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• v.3 no.3
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• pp.201-212
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• 2000

Recent seismicity of the central region of South Korea is investigated by using the micro-earthquake data recorded at the seismic network of KNUE(Korea National University of Education) since December, 1997. About two earthquakes are observed each month, which indicates relatively low seismic activities of the region, without showing any temporal characteristics of seismicity. The b-value of the region obtained from the data we used is found to be about 1.15. The epicenters of the micro-earthquakes are mostly located in the Okchon Zone, especially around Munkyong area, Poeun-Sokri Mt.-Youngdong area, and Kunsan-Nonsan area.

• Journal of the Korean GEO-environmental Society
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• v.20 no.6
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• pp.15-22
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• 2019

In this study, the hazard areas are identified by using the Newmark displacement model, which is a predictive model for identifying the areas at risk of landslide triggered by earthquakes, based on the results of field survey and laboratory test, and literature data. The Newmark displacement model mainly utilizes earthquake and slope related data, and the safety of slope stability derived from LSMAP, which is a landslide prediction program. Backyang Mt. in Busan where the landslide has already occurred, was chosen as the study area of this research. As a result of this study, the area of landslide prone zone identified by using the Newmark displacement model without earthquake factor is about 1.15 times larger than that identified by using LSMAP.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.3-7
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• 2005

Focal mechanism of the real and imaginary faults in the western coast of Japan has been assumed by examining the previous studies on the seismicity, seismic gap, fault behaviors, seismic zoning, and faults. In the area of no seismic information, the focal mechanism has been assumed to have the maximum influence on the tsunami height in the eastern coast of Korea. The tsunami height in a particular point of the eastern coast of Korea can vary up to 7 orders with the variation of the strike of the fault in a particular source point of the western coast of Japan with constant magnitude. Tsunami scenario DB including tile arrival times and tsunami heights has been constructing by using the assumed focal mechanism of the western coast of Japan. Tsunami warning system will be reinforced by using this tsunami scenario DB near future.

• Journal of the Korean Geophysical Society
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• v.8 no.2
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• pp.93-96
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• 2005

Focal mechanism of the real and imaginary faults in the western coast of Japan has been assumed by examining the previous studies on the seismicity, seismic gap, fault behaviors, seismic zoning, and faults. In the area of no seismic information, the focal mechanism has been assumed to have the maximum influence on the tsunami height in the eastern coast of Korea. The tsunami height in a particular point of the eastern coast of Korea can vary up to 7 orders with the variation of the strike of the fault in a particular source point of the western coast of Japan with constant magnitude. Tsunami scenario DB including the arrival times and tsunami heights has been constructing by using the assumed focal mechanism of the western coast of Japan. Tsunami warning system will be reinforced by using this tsunami scenario DB near future.

• Journal of the Korean Geotechnical Society
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• v.28 no.5
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• pp.55-65
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• 2012

The purpose of this study is to estimate seismic damage for harbor site considering dynamic amplification characteristics. First of all, a series of ground response analysis is performed and then correlation equations between rock outcrop accelerations and peak ground accelerations (PGAs) are determined. These equations are saved into DB and when an earthquake occurs, PGAs are determined by them as soon as possible. For earthquake events, seismic damage grades of harbor structures are determined by using the correlated PGAs and fragility curves of harbor structures in real time. In this study, seismic damage was estimated and classified into several grades by applying two hypothetical earthquakes.

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.78.2-78.2
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• 2010

2008년 6월 14일, 일본 이와테(암수(岩手)) 미야기(궁성(宮城)) 내륙 지진이 발생하였다. 평야지역에서의 피해는 경미하였지만, 산간지역은 괴멸적인 피해를 입은 것이 가장 큰 특정이다. 특히, 산간지역의 간이수도 등, 소규모 수도 시설의 지하수원이 고갈되고 정수시설의 경사면이 붕괴되는 등의 피해를 입었다. 또, 지진발생 후, 원수의 높은 탁도와 색도가 시간이 경과한 시점에서도 낮아지거나 없어지지 않았던 곳이 많았다. 이번 연구보고에서는, 간이수도 등의 피해와 상호지원 체제의 상황을 보고함과 동시에 소규모 수도시설의 지진 재해에 대한 제언을 제시하고자 하였다.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.951-958
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• 2018

Catastrophic tsunamis triggered by undersea earthquakes may invade not only neighboring but also distant coastal communities. Many coastal communities and nuclear power plants are located along the Eastern Coast of the Korean Peninsula and they may be very vulnerable to unexpected tsunami attacks. In this companion review, field survey of tsunamis, prevention against tsunamis, furture research topics will be described.